Code sequence generation method, modulation apparatus, modulation method, modulation program, demodulation apparatus, demodulation method, demodulation program and storage medium

1. A code sequence generation method for generating a Matched Spectral Null (MSN) code sequence where a null point of a frequency spectrum on a recording channel or communication channel of a code sequence is matched with a null point of a frequency spectrum of a Partial Response (PR) equalized signal including said code sequence, said code sequence generation method comprising: a state transition diagram analyzing step of dividing each state corresponding to a finite state transition diagram, where a value d (d: an integer greater or equal to 1) of minimum run of said MSN code sequence is restricted and a value of Alternating Digital Sum (ADS) of said code sequence on a Not Return to Zero Inverse (NRZI) method is also restricted into d+1 states in based on a preceding code sequence that is comprised of d codes output immediately before, and restricting transition to a next state in accordance with said preceding code sequence to form a finite division state transition diagram where output of codes on the transition to said next state is restricted; and a code sequence generation step of generating, in accordance with said finite division state transition diagram, a MSN code sequence where output of consecutive codes of “1” on said NRZI method is prohibited and a minimum run is limited to be greater or equal to one.

2. The code sequence generation method according to claim 1 , wherein if a code of “1” is included in said preceding code sequence associated with each said divided state, the output is restricted so that a code of “0” is output before moving to said next state.

3. The code sequence generation method according to claim 1 , wherein the state transition diagram is formed such that two states that have the same absolute value of said SDS are reduced to one state.

4. The code sequence generation method according to claim 1 , wherein said code sequence generation step provides transitions n times (n: an integer greater or equal to one) from a predetermined initial state to a predetermined end state on said finite division state transition diagram to generate said code sequence with code length n.

5. The code sequence generation method according to claim 2 , wherein if said minimum run is limited to one, said finite division state transition diagram where each state of said finite state transition diagram is divided into two states corresponding to two patterns of said preceding code sequences of “0” and “1” and there is restriction to output a code of “0” when a state with said preceding code sequence of “1” is a next state.

6. The code sequence generation method according to claim 5 , wherein said code sequence generation step sets a state that has said value of ADS of “0” on said finite division state transition diagram and comes immediately after outputting a code of “0” to initial and end states, and repeats the state transition twenty six times to generate said MSN code sequence with code length of 26.

7. The code sequence generation method according to claim 5 , wherein said code sequence generation step includes a run limitation step of limiting a top run indicating the maximum number of consecutive codes of “0” that starts from a top of said MSN code sequence, an end run indicating the maximum number of consecutive codes of “0” that continues to an end of said MSN code sequence, and a middle run indicating the maximum number of consecutive codes of “0” on a middle part excluding the consecutive parts of symbols of “0” on said top and end of said MSN code sequence to a predetermined value to extract, out of a plurality of said MSN code sequences output in accordance with said finite division state transition diagram, said code sequences that are restricted such that a maximum run between said adjoining MSN code sequences or in one of said MSN code sequences is limited to be less or equal to a predetermined value.

8. The code sequence generation method according to claim 7 wherein: said code sequence generation step sets a state that has said value of ADS of “0” on said finite division state transition diagram and comes immediately after outputting a code of “0” to initial and end states, and repeats the state transition twenty six times to generate said MSN code sequence with code length of 26; and said run limitation step limits said middle run to fourteen, said top run to six and said end run to eight to extract said MSN code sequence where the maximum run between said adjoining MSN code sequences or in one of said MSN code sequences is limited to fourteen.

9. The code sequence generation method according to claim 7 , wherein said run limitation step limits said middle run to fourteen, said top run to seven and said end run to seven to extract said MSN code sequence where the maximum run between said adjoining MSN code sequences or in one of said MSN code sequences is limited to fourteen.

10. The code sequence generation method according to claim 7 , wherein said code sequence generation step includes a RMTR limitation step performing the process of: setting the maximum number of repetition (Repeated Minimum Transition Run-length (RMTR)) of a shortest run code sequence of “10” whose run from a top part of said MSN code sequence is the smallest when a code sequence on said top part is “101” as a positive top RMTR; setting said RMTR that continues to an end part of said MSN code sequence when a code sequence on said end part is “010” as a positive end RMTR; setting said RMTR on a part excluding the part where said shortest run codes repeatedly appear from said top and the part where said shortest run codes repeatedly appear to said end when the code sequence on said top part of said MSN code sequence is “101” as a positive middle RMTR; setting said RMTR that continues from said top part when the code sequence on said top part of said MSN code sequence is “010” as a negative top RMTR; setting said RMTR that continues to said end part when the code sequence on said end part of said MSN code sequence is “101” as a negative end RMTR; setting said RMTR on a part excluding the part said shortest run code sequences repeatedly appear from said top and the part where said shortest run code sequences repeatedly appear to said end when the code sequence on the top part of said MSN code sequence is “010” as a negative middle RMTR; and limiting said positive middle RMTR, said positive top RMTR, said positive end RMTR, said negative middle RMTR, and said negative top RMTR to a predetermined value to extract, out of a plurality of MSN code sequences output in accordance with said finite division state transition diagram, said code sequences where said RMTR between said adjoining MSN code sequences or in one of said MSN code sequences is restricted.

11. The code sequence generation method according to claim 10 , wherein: said run limitation step limits said middle run to fourteen, said top run to six and said end run to eight to extract said MSN code sequence where the maximum run between said adjoining MSN code sequences or in one of said MSN code sequences is limited to fourteen; and said RMTR limitation step limits said positive middle RMTR to ten, said positive top RMTR to four, said positive end RMTR to five, said negative middle RMTR to ten and said negative top RMTR to ten to extract said MSN code sequence where the RMTR between said adjoining MSN code sequences or in one of said MSN code sequences is limited to ten.

12. The code sequence generation method according to claim 10 , wherein: said run limitation step limits said middle run to fourteen, said top run to seven and said end run to seven to extract said MSN code sequence where the maximum run between said adjoining MSN code sequences or in one of said MSN code sequences is limited to fourteen; and said RMTR limitation step limits said positive middle RMTR to ten, said positive top RMTR to four, said positive end RMTR to five, said negative middle RMTR to ten and said negative top RMTR to ten to extract said MSN code sequence where the RMTR between said adjoining MSN code sequences or in one of said MSN code sequences is limited to ten.

13. The code sequence generation method according to claim 2 , wherein said state transition diagram formation step forms, if the minimum run of said MSN code sequence is limited to two, said finite division state transition diagram where each state of said finite state transition diagram is divided into three states corresponding to three patterns of said preceding code sequences of “00”, “01 and “10” and there is restriction to output a code of “0” when a state with said preceding code sequence of “01” or “10” moves to a next state.

14. The code sequence generation method according to claim 13 , wherein said code sequence generation step sets a state that has the value of ADS of “−1” on said finite division state transition diagram and comes immediately after outputting a code of “00” to initial and end states, and repeats the state transition thirty four times to generate said code sequence with code length of 34.

15. The code sequence generation method according to claim 13 , wherein said code sequence generation step includes a run limitation step of limiting a top run indicating the maximum number of consecutive codes of “0” that starts from a top of said MSN code sequence, an end run indicating the maximum number of consecutive codes of “0” that continues to an end of said MSN code sequence, and a middle run indicating the maximum number of consecutive codes of “0” on a middle part excluding the consecutive parts of symbols of “0” on said top and end of said MSN code sequence to a predetermined value to extract, out of a plurality of said MSN code sequences output in accordance with said finite division state transition diagram, said code sequences that are restricted such that a maximum run between said adjoining MSN code sequences or in one of said MSN code sequences is limited to be less or equal to a predetermined value.

16. The code sequence generation method according to claim 13 , wherein: said code sequence generation step sets a state that has said value of ADS of “−1” on said finite division state transition diagram and comes immediately after outputting a code of “0” to initial and end states, and repeats the state transition thirty four times to generate said MSN code sequence with code length of 34; and said run limitation step limits said middle run to thirty, said top run to fourteen and said end run to sixteen to extract said MSN code sequence where the maximum run between said adjoining code sequences or in one of said code sequences is limited to thirty.

17. The code sequence generation method according to claim 15 , wherein said code sequence generation step includes a RMTR limitation step performing the process of: setting the maximum number of repetition (RMTR) of a shortest run code sequence of “100” whose run from a top part of said MSN code sequence is the smallest when a code sequence on said top part is “1001” as a positive top RMTR; setting said RMTR that continues to an end part of said MSN code sequence when a code sequence on said end part is “0100” as a positive end RMTR; setting said RMTR on a part excluding the part where said shortest run codes repeatedly appear from said top and the part where said shortest run codes repeatedly appear to said end when the code sequence on said top part of said MSN code sequence is “1001” as a positive middle RMTR; and limiting said positive middle RMTR, said positive top RMTR and said positive end RMTR to a predetermined value to extract, out of a plurality of MSN code sequences output in accordance with said finite division state transition diagram, said code sequences where said RMTR between said adjoining MSN code sequences or in one of said MSN code sequences is restricted.

18. The code sequence generation method according to claim 17 , wherein: said run limitation step limits said middle run to thirty, said top run to fourteen and said end run to sixteen to extract said MSN code sequence where the maximum run between said adjoining code sequences or in one of said code sequences is limited to thirty; and said RMTR limitation step limits said positive middle RMTR to six, said positive top RMTR to two and said positive end RMTR to three to extract said code sequence where the RMTR between said adjoining code sequences or in one of said code sequences is limited to six.

19. A data encoding apparatus comprising a correlation table where a data sequence with a predetermined number of bits is associated with a code sequence with a predetermined number of bits, said data sequence being translated into said code sequence to allow a predetermined demodulation section to demodulate said code sequence into said data sequence in accordance with said correlation table, wherein said code sequence is NRZI format comprising a MSN code sequence where a null point of a frequency spectrum on a recording channel or communication channel of said code sequence is matched with a null point of a frequency spectrum of a PR equalized signal including said code sequence and a minimum run length is limited to be greater or equal to one.

20. The data encoding apparatus according to claim 19 , wherein said data sequence is 16 bits; and a minimum run length of said MSN code sequence is limited to one and said MSN code sequence's code length is 26 bits.

21. The data encoding apparatus according to claim 20 , wherein said MSN code sequence is restricted such that a top run indicating the maximum number of consecutive codes of “0” that starts from a top of said MSN code sequence is limited to six, an end run indicating the maximum number of consecutive codes of “0” that continues to an end of said MSN code sequence is limited to eight, and a middle run indicating the maximum number of consecutive codes of “0” on a middle part excluding the consecutive parts of symbols of “0” on said top and end of said MSN code sequence is limited to fourteen.

22. The data encoding apparatus according to claim 21 , wherein said MSN code sequence is restricted such that said top run is limited to seven, said end run is limited to seven and said middle run is limited to fourteen.

23. The data encodes apparatus according to claim 20 , wherein said MSN code sequence is restricted such that a positive top RMTR indicating the maximum number of repetition (RMTR) of a shortest run code sequence of “10” whose run from a top part of said MSN code sequence is the smallest when a code sequence on said top part is “101” is limited to four; a positive end RMTR indicating said RMTR that continues to an end part of said MSN code sequence when a code sequence on said end part is “010” is limited to five; a positive middle RMTR indicating said RMTR on a part excluding the part where said shortest run codes repeatedly appear from said top and the part where said shortest run codes repeatedly appear to said end when the code sequence on said top part of said MSN code sequence is “101” is limited to ten; a negative top RMTR indicating said RMTR that continues from said top part when the code sequence on said top part is “010” is limited to ten; and a negative middle RMTR indicating said RMTR on a part excluding the part where said shortest run code sequences repeatedly appear from said top and the part where said shortest run code sequences repeatedly appear to said end when the code sequence on said top part is “010” is limited to ten.

24. The data encoding apparatus according to claim 20 , wherein said MSN code sequence is restricted such that a positive top RMTR indicating the maximum number of repetition (RMTR) of a shortest run code sequence of “10” whose run from a top part of said MSN code sequence is the smallest when a code sequence on said top part is “101” is limited to four; a positive end RMTR indicating said RMTR that continues to an end part of said MSN code sequence when a code sequence on said end part is “010” is limited to five; a positive middle RMTR indicating said RMTR on a part excluding the part where said shortest run codes repeatedly appear from said top and the part where said shortest run codes repeatedly appear to said end when the code sequence on said top part of said MSN code sequence is “101” is limited to ten; a negative top RMTR indicating said RMTR that continues from said top part when the code sequence on said top part is “010” is limited to ten; and a negative middle RMTR indicating said RMTR on a part excluding the part where said shortest run code sequences repeatedly appear from said top and the part where said shortest run code sequences repeatedly appear to said end when the code sequence on said top part is “010” is limited to ten.

25. The data encoding apparatus according to claim 19 , wherein said data sequence is 16 bits; and a minimum run of said MSN code sequence is limited to two and said MSN code sequence's code length is 34 bits.

26. The data encoding apparatus according to claim 19 , wherein said MSN code sequence is restricted such that a top run indicating the maximum number of consecutive codes of “0” that starts from a top of said MSN code sequence is limited to fourteen, an end run indicating the maximum number of consecutive codes of “0” that continues to an end of said MSN code sequence is limited to sixteen, and a middle run indicating the maximum number of consecutive codes of “0” on a middle part excluding the consecutive parts of symbols of “0” on said top and end of said MSN code sequence is limited to thirty.

27. The data encoding apparatus according to claim 26 , wherein said MSN code sequence is restricted such that a positive top RMTR indicating the maximum number of repetition (RMTR) of a shortest run code sequence of “100” whose run from a top part of said MSN code sequence is the smallest when a code sequence on said top part is “1001” is limited to fourteen; a positive end RMTR indicating said RMTR that continues to an end part of said MSN code sequence when a code sequence on said end part is “0100” is limited to sixteen; and a positive middle RMTR indicating said RMTR on a part excluding the part where said shortest run codes repeatedly appear from said top and the part where said shortest run codes repeatedly appear to said end when the code sequence on said top part of said MSN code sequence is “1001” is limited to thirty.

28. The data encoding apparatus according to claim 19 , wherein said data encoding section includes: block modulation means for dividing said data sequentially input into (m×M−1)-bit addition data blocks (M: an integer greater or equal to two) of said data sequence, and sequentially modulating, in accordance with said correlation table, (M−1) data sequences each of which includes m×(M−1)-bit data obtained from a top of said addition data block into (M−1) MSN code sequences; addition modulation means for generating two types of addition data by adding an additional bit of “0” or “1” to said data sequence including (m−1)-bit data obtained from an end of said addition data block, and modulating, in accordance with said correlation table, said two types of addition data into two types of addition code sequences; storage means for temporarily storing said two types of addition code sequences and (M−1) MSN code sequences modulated after said addition code sequences; and addition code sequence selection means for performing Direct Current (DC) control of said code sequence by calculating Digital Sum Values (DSV) of M code sequences in a case in which said (M−1) MSN code sequences are output from said storage means after said two types of addition code sequences, selecting one whose DSV is closer to zero out of said two types of addition code sequences, and sequentially outputting the selected addition code sequence along with said (M−1) MSN code sequences.

29. A data encoding method executed by a microprocessor controlled system comprising: generating a signal in accordance with a correlation table where a data sequence with a predetermined number of bits is translated into a code sequence with a predetermined number of bits, said data sequence being translated as said code sequence to allow a demodulation section to demodulate said code sequence into said data sequence in accordance with said correlation table, wherein said code sequence is NRZI format comprised of a MSN code sequence where a null point of a frequency spectrum on a recording channel or communication channel of said code sequence is matched with a null point of a frequency spectrum of a PR equalized signal including said code sequence and a minimum run length is limited to be greater or equal to one.

30. A data encoding program executed by a microprocessor controlled system for causing the microprocessor controlled system to execute: data encoding in accordance with a correlation table where a data sequence with a predetermined number of bits is associated with a code sequence with a predetermined number of bits, said data sequence being translated into said code sequence to allow a decoding section to decode said code sequence into said data sequence in accordance with said correlation table, wherein said code sequence NRZI format comprised of a MSN code sequence where a null point of a frequency spectrum on a recording channel or communication channel of said code sequence is matched with a null point of a frequency spectrum of a PR equalized signal including said code sequence and a minimum run length is limited to be greater or equal to one.

31. A data decoding apparatus comprising: a decoding section that decodes a signal in accordance with a correlation table where a data sequence with a predetermined number of bits is associated with a code sequence with a predetermined number of bits, said code sequence having been previously generated by translating said data sequence into said code sequence, wherein said code sequence is NRZI format comprised of a MSN code sequence where a null point of a frequency spectrum on a recording channel or communication channel of said code sequence is matched with a null point of a frequency spectrum of a PR equalized signal including said code sequence and a minimum run is limited to be greater or equal to one.

32. The data decoding apparatus according to claim 31 , wherein said data sequence is 16 bits; and a minimum run length of said MSN code sequence is limited to one and said MSN code sequence's code length is 26 bits.

33. The data decoding apparatus according to claim 32 , wherein said MSN code sequence is restricted such that a top run indicating the maximum number of consecutive codes of “0” that starts from a top of said MSN code sequence is limited to six, an end run indicating the maximum number of consecutive codes of “0” that continues to an end of said MSN code sequence is limited to eight, and a middle run indicating the maximum number of consecutive codes of “0” on a middle part excluding the consecutive parts of symbols of “0” on said top and end of said MSN code sequence is limited to fourteen.

34. The data decoding apparatus according to claim 33 , wherein said MSN code sequence is restricted such that said top run is limited to seven, said end run is limited to seven and said middle run is limited to fourteen.

35. The data decoding apparatus according to claim 33 , wherein said MSN code sequence is restricted such that a positive top RMTR indicating the maximum number of repetition (RMTR) of a shortest run code sequence of “10” whose run from a top part of said MSN code sequence is the smallest when a code sequence on said top part is “101” is limited to four; a positive end RMTR indicating said RMTR that continues to an end part of said MSN code sequence when a code sequence on said end part is “010” is limited to five; a positive middle RMTR indicating said RMTR on a part excluding the part where said shortest run codes repeatedly appear from said top and the part where said shortest run codes repeatedly appear to said end when the code sequence on said top part of said MSN code sequence is “101” is limited to ten; a negative top RMTR indicating said RMTR that continues from said top part when the code sequence on said top part is “010” is limited to ten; and a negative middle RMTR indicating said RMTR on a part excluding the part where said shortest run code sequences repeatedly appear from said top and the part where said shortest run code sequences repeatedly appear to said end when the code sequence on said top part is “010” is limited to ten.

36. The data decoding apparatus according to claim 34 , wherein said MSN code sequence is restricted such that a positive top RMTR indicating the maximum number of repetition (RMTR) of a shortest run code sequence of “10” whose run from a top part of said MSN code sequence is the smallest when a code sequence on said top part is “101” is limited to four; a positive end RMTR indicating said RMTR that continues to an end part of said MSN code sequence when a code sequence on said end part is “010” is limited to five; a positive middle RMTR indicating said RMTR on a part excluding the part where said shortest run codes repeatedly appear from said top and the part where said shortest run codes repeatedly appear to said end when the code sequence on said top part of said MSN code sequence is “101” is limited to ten; a negative top RMTR indicating said RMTR that continues from said top part when the code sequence on said top part is “010” is limited to ten; and a negative middle RMTR indicating said RMTR on a part excluding the part where said shortest run code sequences repeatedly appear from said top and the part where said shortest run code sequences repeatedly appear to said end when the code sequence on said top part is “010” is limited to ten.

37. The data decoding apparatus according to claim 31 , wherein said data sequence is 16 bits; and a minimum run length of said code sequence is limited to two and said code sequence's code length is 34 bits.

38. The data decoding apparatus according to claim 37 , wherein said MSN code sequence is restricted such that a top run indicating the maximum number of consecutive codes of “0” that starts from a top of said MSN code sequence is limited to fourteen, an end run indicating the maximum number of consecutive codes of “0” that continues to an end of said MSN code sequence is limited to sixteen, and a middle run indicating the maximum number of consecutive codes of “0” on a middle part excluding the consecutive parts of symbols of “0” on said top and end of said MSN code sequence is limited to thirty.

39. The data decoding apparatus according to claim 38 , wherein said MSN code sequence is restricted such that a positive to RMTR indicating the maximum number of repetition (RMTR) of a shortest run code sequence of “100” whose run from a top part of said MSN code sequence is the smallest when a code sequence on said top part is “1001” is limited to fourteen; a positive end RMTR indicating said RMTR that continues to an end part of said MSN code sequence when a code sequence on said end part is “0100” is limited to sixteen; and a positive middle RMTR indicating said RMTR on a part excluding the part where said shortest run codes repeatedly appear from said top and the part where said shortest run codes repeatedly appear to said end when the code sequence on said top part of said MSN code sequence is “1001” is limited to thirty.

40. The data decoding apparatus according to claim 31 further comprising a Trellis Coded Partial Response Maximum Likelihood (TCPRML) detection section that detects said code sequence by performing a Partial Response (PR) equalization process and a maximum likelihood decoding process on a signal acquired through said transmission channel in accordance with a trellis configuration generated based on a PR equalized state transition diagram where a minimum value d of run is limited to be greater or equal to one and a finite division state transition diagram.

41. The data decoding apparatus according to claim 40 , wherein said trellis configuration is associated with the passage of time, including a path that allows to move to a possible state at each time and from said state to a state at next time.

42. The data decoding apparatus according to claim 41 , wherein said data sequence is 16 bits; a minimum run of said MSN code sequence is limited to one and said MSN code sequence is 26 bits; and said trellis configuration is generated based on a state transition diagram corresponding to PR(1,1).

43. The data decoding apparatus according to claim 41 , wherein said data sequence is 16 bits; a minimum run of said MSN code sequence is limited to one and said MSN code sequence is 26 bits; and said trellis configuration is generated based on a state transition diagram corresponding to PR(1,1+x,x) (x: any real number).

44. The data decoding apparatus according to claim 41 , wherein said data sequence is 16 bits; a minimum run of said MSN code sequence is limited to one and said MSN code sequence is 26 bits; and said trellis configuration is generated based on a state transition diagram corresponding to PR(1,1+a,a+b,b) (a and b: any real number).

45. The data decoding apparatus according to claim 31 , wherein said MSN code sequence is modulated for each m-bit data in accordance with said correlation table from addition data where each (M×m−1) bit data (M: an integer greater or equal to one) is associated with an additional bit to bring DSV of said MSN code sequence close to zero, wherein said data decoding section further includes: data decoding means for sequentially decoding, in accordance with said correlation table, said MSN code sequence into said data sequence; and additional bit removal means for removing said additional bit from each of M data sequences to extract an original data sequence.

46. A data decoding method executed by a microprocessor controlled system comprising: decoding a signal in accordance with a correlation table where a data sequence with a predetermined number of bits is associated with a code sequence with a predetermined number of bits, said code sequence having been previously generated by translating said data sequence into said code sequence, wherein said code sequence is NRZI format comprising a MSN code sequence where a null point of a frequency spectrum on a recording channel or communication channel of said code sequence is matched with a null point of a frequency spectrum of a PR equalized signal including said code sequence and a minimum run is limited to be greater or equal to one.

47. A data encoding program stored in an electronic memory of an information processing apparatus for causing the information processing apparatus to execute: demodulating a signal in accordance with a correlation table where a data sequence with a predetermined number of bits is associated with a code sequence with a predetermined number of bits, said code sequence having been previously generated by translating said data sequence into said code sequence, wherein said code sequence is NRZI format comprising a MSN code sequence where a null point of a frequency spectrum on a recording channel or communication channel of said code sequence is matched with a null point of a frequency spectrum of a PR equalized signal including said code sequence and a minimum run is limited to be greater or equal to one.

48. A storage medium storing a plurality of code sequences with predetermined bits that have been translated from data with predetermined bits, wherein the code sequences are demodulated in accordance with a correlation table such that a data sequence with a predetermined number of bits is associated with a code sequence with a predetermined number of bits, said code sequence having been previously generated by translating corresponding data sequences into said plurality of code sequences, each said code sequence is NRZI format comprising a MSN code sequence where a null point of a frequency spectrum on said storage medium is matched with a null point of a frequency spectrum of a PR equalized reproduction signal including said code sequence and a minimum run is limited to be greater or equal to one.